prob...

hey, i was playin the other day, and i lean out to shoot out the side of the beer can, when psshhh, all the the air starts leaking out of my barrel...i check it, turn the air off and walk off...
i think it's an o-ring but where?
i checked the lpr/hpr, is it in by the poppet?
i have an 05 empire timmy.